"> Caterpillar MaK 6L M552C
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Caterpillar MaK

6L M552C

The Caterpillar MaK 6L M552C is a legacy medium‑speed, four‑stroke inline‑six diesel engine delivering high torque at low rpm for main propulsion on older merchant vessels.

5520.0 kW
Power

Engine Specifications

6
Cylinders
552 mm
Bore
720 mm
Stroke

Components & Design

Component data being added…

Technical Data

Bore 450 mm
Stroke M551 550 mm
Stroke M552 520 mm
Output per cylinder 780 bhp (M551 @ 425 rpm) / 835 bhp (M552 @ 500 rpm)
SFOC (8-cyl economy) 130 g/bhp-h
Lubrication oil inlet 50-55 °C
Oil pressure 4.0-5.0 bar
Valve guide clearance limit 0.40 mm (inlet & exhaust)
Fuel capability up to 7,000 sec Redwood I @ 100 °F
configuration L
rpm 400
fuel type HFO
technology Mechanical Heavy-Duty Trunk Piston
displacement l per cyl 172.3

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Common failures & inspection points

Valve guide wear and excessive clearance (>0.40 mm) leading to hot gas leakage and loss of compression

Measure valve guide clearance in cross-direction; check for elevated crankcase pressure

Piston crown erosion/burning from fuel injection system degradation or premature injection timing

Borescope inspection for crown material loss; check fuel injection pressure & timing

Turbocharger bearing wear and oil starvation (legacy medium-speed engines prone to lube oil management issues)

Check turbo shaft play; inspect oil feed/drain lines for blockage

Connecting rod bearing clearance drift and main bearing wear (long-stroke design, 50+ year old engines)

Measure bearing clearance with Plastigage; inspect crankshaft for ovality

Type-general inspection and maintenance points for this equipment category — not model-specific.

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Equipment Model #66557 · discontinued